A) y=-5x⁵+2x+3
D(y)=(-∞; +∞)
б) у=7х³ -1
х+4
х+4≠0
х≠-4
х∈(-∞; -4)U(-4; +∞)
D(y)=(-∞; -4)U(-4; +∞)
в) у=√(-х²+5х+6)
-х²+5х+6≥0
f(x)=-x²+5x+6 - парабола, ветви направлены вниз
-х²+5х+6=0
х²-5х-6=0
D=25-4*(-6)=49
x₁=5-7= -1
2
x₂=5+7=6
2
- + -
--------- -1 ----------- 6 ---------------
\\\\\\\\\\\\\
x∈[-1; 6]
D(y)=[-1; 6]
г) у= х
√(х²-4)
{√(x²-4)≠0
{x²-4≥0
x²-4>0
(x-2)(x+2)>0
x=2 x=-2
+ - +
-------- -2 ----------- 2 ------------
\\\\\\\\\ \\\\\\\\\\\\
x∈(-∞; -2)U(2; +∞)
D(y)=(-∞; -2)U(2; +∞)